It is proposed to study interactions between weak ultra high frequency (450 MHz) electromagnetic fields and the central nervous system. These studies will continue research that has disclosed power windows and modulation frequency windows for these interactions. Neurochemistry: Studies of interactions between weak electromagnetic fields and calcium ion binding in the central nervous system will be continued and will serve as reference for experiments involving amino acid and other putative neurotransmitters. Chick and cat cerebral tissues will be compared in their response to field stimulation. Behavior: Performances of neonate chicks and ducklings exposed to 450 MHz fields will be compared in a series of behavioral measurements ranging from free behavior to sophisticated behavioral tasks, including variation of an interresponse time schedule. Schedule-controlled behavior in monkeys will be tested under similar field conditions. Tissue dosimetry: In collaboration with Dr. H.I. Bassen (BRH), there will be continued collaboration in measurements of field gradients in tissue as correlates of neurochemical responses. Theoretical interpretation: Recent developments in theoretical physics will be applied in modeling non-linear responses of the central nervous system to weak perturbations of the extracellular environment.